Correct some issues with being banned. See #658 which may be relevant

proxy/src/main/java/net/md_5/bungee/ServerConnector.java

@@ -218,6 +218,8 @@ public class ServerConnector extends PacketHandler
         {
             user.sendMessage( message );
         }
+
+        throw new CancelSendSignal();
     }
 
     @Override